Abstract

A device for temporarily locking two portions (4a, 4b) of a bone after they have been separated during an osteotomy operation, comprising at least one member securable to both portions (4a, 4b) of the bone. The device is characterised in that said member comprises abutment means and the spacing (a) between the outer surfaces thereof is the same as the spacing to be achieved between the bone portions (4a, 4b), said means being engageable with said portions to hold them apart with said spacing (a).

Description

DEVICE DEBLOCAGETEMPORAIREDE DEUXPARTIESD'UNEPIECEOSSEUSE

The present invention relates to a temporary locking device of the type used in osteotomy procedures including open tibial osteotomy. It is known that in this type of procedure, the surgeon, after having carried out a partial transverse cut of the upper part of a piece of bone and in particular of a tibia, rotates relative to the other two cut portions in order to restore the angle between the anatomical and mechanical axes of said bone piece the desired value. The holding in position of the two cutout portions is then usually provided by staples or bone plates which are secured longitudinally thereon. a difficulty of this type of operation is known to maintain relative to the other of the two cut portions at a specific distance given during the time necessary for the consolidation of the bone.

The present invention aims to remedy this drawback by providing a locking device of two cut-out portions of a bone part, in particular of a tibia, which allows a preset gap to be provided between these two parts for their give the desired angle, and ensures a positive maintaining this separation gave up the consolidation of the bone.

The present invention thus provides a temporary locking device for two parts of a bone part separated during an osteotomy operation, comprising at least one securable member of said two parts of the bone part, characterized in that this element comprises abutment means, the spacing of the end faces is equal to that which is desired to separate said portions of the bone part and which are intended to bear against the latter, so as to maintain them with said determined spacing.

In a first mode of implementation of the invention the two stop means are arranged on a single piece, to a predetermined fixed distance, so that the surgeon will have available a sampling of such devices which will stop means more or less spaced apart depending on the work to be performed.

In a second interesting embodiment of the invention the spacing of the stop means is adjustable and the locking device thus comprises two mobile elements mounted for longitudinal movement relative to each other and fixed respectively on both parts of the bone part, and locking means of the two movable elements with respect to one another in several predetermined positions.

The implementation of such a device according to the invention is particularly easy since it makes it possible, before being put in place, the preset gap of the stop means, and therefore one of the two cutting faces of the two parts bone piece, the 0

desired value. It is thus possible, with a single device, to obtain a wide range of angular deviations. Moreover, it is easy to get high accuracy because the preset can be performed outside of the various technical constraints typically encountered on an operating site.

In a variant of this embodiment of the invention, the two mobile elements are constituted respectively of a slide having a longitudinal recess, and a slider adapted to move in different pre-adjustable positions thereof.

The locking means may consist in particular of teeth, of complementary shapes provided on the inner edges respectively of the recess and on the outer edges of the slide, these teeth being substantially perpendicular to the contact face of the slide and the slide with the bone part. hereinafter be described, by way of example, in various embodiment of the invention with reference to the accompanying drawings in which:

Figure 1 is a longitudinal sectional view of a locking device according to the invention when placed in place on a tibia.

Figure 2 is an elevation of the locking device shown in FIG 1. FIG 3 is an exploded perspective view of another form of implementation of an immobilising device according to the invention.

Figure 4 is a longitudinal sectional view of the device shown in Figure 3 once it placed on a tibia.

Figure 5 is a partial sectional view along the line VV of Figure 4.

Figure 6 is a perspective view of a third embodiment of a locking device according to the invention.

Figure 7 is a sectional view of the device shown in Figure 6 along the line VII-VII thereof. Figure 8 is a longitudinal sectional view of the device shown in Figure 6 once the latter in place on a tibia.

Figure 9 is a sectional view of the device shown in Figures 6 to 8, this device being set in a minimum gap position.

Figure 10 is a partial plan view of an alternative embodiment of the invention.

Figure 11 is a partial sectional view on a larger scale of an alternative embodiment of the invention.

Figure 12 is a perspective view of another implementation variant to the invention. The temporary locking device according to the invention shown in Figures 1 and 2 comprises a wafer 1 made of a biocompatible material, in particular stainless steel, which comprises at each of its ends a head 2 each having two holes 3. The fastening plate

1 comprises, on its inner face, that is to say on the face intended to come into contact with each of two portions

4a and 4b of a tibia, two retaining tabs, namely an upper leg 6a and a lower leg 6b. Legs 6a and 6b have their upper and lower end faces separated by a distance a ^ corresponding to that which is desired to separate the portions 4a and 4b of the tibia, so that the surfaces 7a and 7b corresponding to the cut effected form an angle α value desired by the practitioner.

Preferably, as shown in Figure 1, the external end faces of the legs 6a and 6b are inclined with respect to the inner face of the wafer 1 so that they are substantially coplanar to the faces

7a, 7b so as to improve their contact with the latter.

The practitioner will have a sampling of wafers 1, the spacing of which are end faces of the legs 6a and 6b will be varied in order to enable it to obtain a range of desired angles α.

The establishment of the wafer 1 is done in an easy manner since, once the legs 6a, 6b slid between the two portions 7a and 7b of the tibia, the latter. because of the pressure they exert on the legs, ensure provisional holding of the wafer 1 for the time necessary for the surgeon to dispose in the holes 3 of the screws to secure the plate 1 on the two parts 4a and 4b of tibia .

In the present invention the surgeon gets easily and with high accuracy angle α desired, without the different stresses that occur during an operation shall affect the accuracy of the work. Moreover, the two sides 4a and 4b of the bone part are completely blocked, promoting reformation and consolidation of the bone.

Of course, the wafer 1 can be made in two parts, so as to make adjustable the distance a ^ of the end faces of the legs 6a and 6b.

The slide 11 consists of an elongate member having a longitudinal and axial groove 17 for receiving the slider 13, and two lateral lugs attachment 19 provided with holes 21. The slide 11 comprises, at its upper part on the drawing, a stop 23 which extends transversely from the side opposite the groove 17. the bottom thereof is pierced with a threaded hole 22. the slider 13 is constituted of an elongated plate which is sized to slide freely in the groove 17. One of its ends, the upper end in the drawing, comprises a double attachment lug 18 provided with two holes 20. near the attachment lug 18 the slide 13 comprises a stop 24 which extends in the same direction as the stop 23 when the slider 13 is in place in the groove 17. the slide 13 further comprises a longitudinal slot 26 of trapezoidal section, the small base of tra Pèze being located on the side coming into contact with the bottom of the groove 17.

The fixing screw 15 comprises a threaded portion 25 intended to be screwed into the threaded hole 22 of the slider 11, followed by a frusto-conical head 27 of which the taper is the same as that of the lumen 26.

Under these conditions, as shown in Figures 4 and 5, when it is desired to immobilize the two parts 4a and 4b of a tibia, so that these two parts form between them an angle α desired, positions the slide 13 in the slide 11 so that the spacing a ^ between the end portions of the two stops 23 and 24 has an appropriate value, determined by calculation, adapted to produce said α angle, and then immobilizes the slide 13 on the slide 11 by applying the conical flanks of the screw 15 against the edges of the slot 26, which is obtained by tightening the screw 15. this is then the device thus blocked b

before both tibia elements 4a and 4b and introduced two stops 23 and 24 therebetween. The force exerted by the two elements of shin 4a and 4b, which tend to approach, ensures the maintenance of the device during the time necessary for its fixation, ie the introduction of fixing screws 31 respectively in the tibia elements 4a and 4b through the holes 20 and 21.

There is shown in Figs 6-9 an alternative embodiment particularly advantageous of the immobilising device according to the invention. This locking device comprises a slide 11 'and a slider 13'.

The slider 11 'is formed of a stainless steel plate which is traversed longitudinally by an aperture 17' that opens at its upper end. The edge of the light 17 * has, over substantially its entire length, of transverse teeth 32 perpendicular to the plane of the plate. The upper portion of the slide 11 'is folded about 90 ° so as to form a stop 23'. The slide 11 'has fastening holes 21'.

The slider 13 'is comprised of an elongated stainless steel element whose cross section has a shape complementary to that of light 17' and its edge has transverse teeth 32 'of complementary shape of the teeth 32 so that it can take place in the light 17 'in virtually any position thereof and find it locked in the longitudinal direction because of the cooperation of its teeth 32' with the teeth 32 of the slide 11 '. It comprises a stop 24 'which extends across the same side as the stop 23' when the slider 13 'is in place in the slide 11'.

The present device is particularly advantageous in that it provides a longitudinal locking of the slide 11 'and the slide 13' which is completely slip-free while being easy to adjust. Furthermore, its installation between the two parts of tibia 4a and 4b is easy to implement because, by exerting a compression force on the two stops 23 'and 24 * in the direction of arrows G, it maintains of the slider 13 'in the slide 11', stress that the practitioner can exert on the two stops 23 'and 24' by entering for example between thumb and forefinger to insert between the two parts of tibia 4a, 4b. Once in place the force exerted by them on the stops 23 'and 24' will continue to provide such maintenance for the time necessary to fixing them with screws 31 '. Once this attachment, the two parts 4a and 4b of the bone piece will find themselves completely blocked during the time necessary for the consolidation of the bone.

Maintaining the slider 13 'in the slider 11' is greatly improved, in particular before the introduction of the assembly between the two bone elements to block, by giving the light 17 'and the branch of the slide 13' a trapezoidal section, the small base of the trapezium being located on the side of the bone part. In a variant of this embodiment of the invention, shown in Figures 8 and 9, one of the stops, i.e. the stop 23 'in the present example, is recessed a cavity 34' whose dimensions are slightly greater than those of the other stop 24 '. It is thus possible to the abutment 24 ', as shown in Figure 9, to be accommodated in the cavity 34', which enables a minimum distance am between the outer faces of the stops 23 'and 24' which is equal to a stop thickness, and thus to obtain a minimum αm small angle of about two degrees.

In order to increase the length of the reach of the stop 24 'on the bone piece member 4a may be as shown in Figure 11, provide a cavity 34' which at least the inner wall located on the side of the bone part when the locking device is in place, comprises a bevel 35 inclined from the top downwards and from the outside inwards, and give the outer surface of the stop 24 'of the slide 13 a complementary inclination.

It is also possible, as shown in Figure 12, provide slightly above the stop 24 ', and at least one side of the slider 13', a zone of least resistance, in particular by means of a groove 37 cross section preferably rounded. This groove 37 is intended to cut in this area, the thickness of the slider 13 '. This implementation mode, when the two members 4a and 4b of the bone part to meet do not form the exact angle presented by the slider 11 'and the slide 13', to bend the latter so that they are in the range both on bone elements 4a and 4b. In another variant of this embodiment of the invention, shown in Figure 10, has been etched a series of graduations 36 on the slide 13 'and a mark 38 on the slide 11', graduations 36 may be labeled with values ​​indicating, when they are opposite the mark 38, the spacing between the stops 23 * and 24 '. It is also possible of course, on the basis of an average diameter of tibia directly perform such a marking in degrees corresponding to the angle α desired. In another embodiment of the invention, the track 11 'is curved transversely so as to better match the shape of the bone part. Thus giving it a certain radius of curvature in the neighboring transverse direction of the average radius of curvature of the bone part.

Can improve the contact of the slider 13 'with the piece of bone by giving it a thickness such that, when in place in the slide 11', it protrudes slightly therefrom on the side intended to come into contact with the workpiece bone. This arrangement allows the slide 13 'to come into contact with the bone piece, even when the radius of curvature in the transverse direction of the piece of bone is higher than that of the slide 11'.

Although the locking devices have been previously described in tibial osteotomy applications it is understood that they could also be used in interventions on other bone parts.

Claims

1.- Device for temporarily locking two portions (4a, b) of a piece of bone separated during an osteotomy operation, comprising at least one element (1, 11, 11 ', 13, 13') securable of said two portions (4a, 4b) of the bone part, characterized in that this element comprises abutment means (6a, 6b, 23,23 ', 24,24'), the spacing (a) of the external faces is equal to that which is desired to separate said portions (4a, 4b) of the bone part and which are intended to bear against the latter, so as to maintain them with said distance (a) determined.

2.- Device according to claim 1 characterized in that said element comprises a zone of least resistance (37) intended to promote its curvature.

3.- Device according to one of claims 1 or 2, characterized in that it comprises two mobile elements (11, 11 ', 13, 13') mounted for longitudinal movement relative to each other and respectively securing to the two parts (4a, 4b) of said bone part, and locking means (15,32) of the two movable elements with respect to one another in several predetermined positions.

4.- Device according to claim 3, characterized in that the two mobile elements are constituted respectively of a slide (11,11 ') having a longitudinal recess (17,17') and a slide (13,13 ') , adapted to move in different pre-adjustable positions thereof.

5.- Device according to claim 4 characterized in that the longitudinal recess (17,17 ') and the slide (13,13') have a trapezoidal section, the small base of the trapezium being located on the side intended to be applied against bone piece.

6.- Device according to one of claims 3 to 5 characterized in that the locking means consist of teeth (32), of complementary shapes respectively provided on the inner edges of the recess (17 ') and on the edges external of the slider (13 '), these teeth (32) being substantially perpendicular to the contact face of the slide (13') and the slide (11 ') with the bone piece.

7.- Device according to one of claims 3 to 6 characterized in that it comprises a first stop (23 ') integral with a mobile element (11') which is provided with a cavity (34 ') adapted to receive, at least partially, a second abutment (24 ') integral with the other mobile element (13').

8.- Device according to claim 7 characterized in that at least the inner wall of the cavity (34 ') on the bone side piece when the locking device is in place, comprises a bevel (35) inclined from the top downwardly and externally inwardly, and the outer face 5

corresponding to the second stop (24 ') has a complementary incline.

9. A device according to one of claims 3 to 8 characterized in that one of the mobile elements (11, 11 ', 13,13') comprises graduations (36), the other mobile element being provided with a marker (38) to know the spacing (a) of the stop elements (23,23 ', 24,24 *) and / or the angle (α) formed by the two portions (4a, 4b) of the bone part, when the device is in place thereon.

10.- Device according to one of the preceding claims characterized in that said element (1, 11, 11 ', 13, 13') made integral the two parts (4a, 4b) of the bone part comprises at least one curved portion in the transverse direction.

PCT/FR1995/0014831994-11-101995-11-10Device for temporarily locking two portions of a bone
WO1996014802A1
(en)